Inhibition of Th1-and enhancement of Th2-initiating cytokines and chemokines in trichosanthin-treated macrophages

Trichosanthin (TCS), the major effective component from Chinese herb Tricho santhes Kirilowii Maxim, is also a potent allergen. Our previous work has s hown that TCS can upregulate interleukin-4 (IL-4) and interleukin-13 (IL-13 ) while inhibit interferon-gamma (IFN-gamma) in mesenteric lymph node cells after TCS immunization. Thus, TCS can arouse a T helper 2 (Th2) response i n the draining lymph node. However, little is known about the early effects of TCS on antigen-presenting cells, the initiator of T cell response. In t he current study, the effects of TCS on macrophage cytokines and chemokine expression were investigated. Peritoneal macrophages were treated with or w ithout TCS in the presence of lipopolysaccharide (LPS). We found that TCS i ncreased macrophage interleukin-10 (IL-10) and monocyte chemoattractant pro tein-1 (MCP-1) expression, whereas it decreased interleukin-12 (IL-12) and tumor necrosis factor-alpha (TNF-alpha) expression. Our study clearly demon strated that TCS, as an allergen, has differential effects on macrophage Th 1/Th2 initiative factors, effects that are likely to facilitate its inducin g of Th2 and immunoglobulin E (IgE) response. (C) 2001 Academic Press.